Electronic combination lock and lock system

ABSTRACT

An electronic lock system utilizes a plurality of remote locking units, each lock unit including a key decoder with a functionally assigned pair of registers containing prestored code combinations. The first register of a pair is designed to store the current combination code. The other register of the pair stores the next or change combination code. When a key coded with said current and change combinations is inserted, the current combination carried by the key is compared with the data stored in each register. If a comparison is made with the first register or the second register, an appropriate access enable signal is provided. In addition, if a comparison is made with the second register, logic circuitry responds to provide a control sequence resulting in a transfer of the change combination code in the second register to the first register, thus becoming therein the current combination code. The key codes can be placed in set positions for current and next codes, or can be separately identified by means of tag codes or the like. The control sequence further causes a new combination code, derived from the multi-coded key, to be placed in the second register as the new change combination code. Thus, the system provides for the use of a multi-coded key for establishing both unlocking and data source functions. A central station utilizes a code generator to appropriately encode the various keys which constitute the sole communication link between the central station and plural access points.

United States Patent Hinman et a1,

[ Jan. 14, 1975 ELETRON1C COMBINATION LOCK AND LOCK SYSTEM [75]Inventors: Bruce E. Hinman, Ridgefield;

Gregory M. Cinque, Stamford; William I). Soltow, Jr., Riverside, all ofConn.

[73] Assignee: Pitney-Bowes, Inc., Stamford, Conn.

[22] Filed: Nov. 1, 1973 [21] Appl. No.: 411,650

[52] U.S. Cl. 340/149 R, 340/147 MD [51] Int. Cl. G06k 7/06, l-l04q 9/00[58] Field of Search 340/147 MD, 149 A, 149 R [56] References CitedUNITED STATES PATENTS 3,732,542 5/1973 Hedin 340/149 A 3,742,453 6/1973Poylo 340/149 A 3,761,892 9/1973 Bosnyak et al. 340/149 A 3,781,80512/1973 ONeal, Jr. 340/147 MD Primary Examiner- Yusko Attorney,Agent, orF irm-William D. Soltow,.lr.; Albert W. Scribner; Donald P. WalkerABSTRACT An electronic lock system utilizes a plurality of remotelocking units, each lock unit including a key decoder with afunctionally assigned pair of registers containing prestored codecombinations. The first register of a pair is designed to store thecurrent combination code. The other register of the pair stores the nextor change combination code. When a key coded with said current andchange combinations is inserted, the current combination carried by thekey is compared with the data stored in each register. If a comparisonis made with the first register or the second register, an appropriateaccess enable signal is provided. In addition, if a comparison is madewith the second register, logic circuitry responds to provide a controlsequence resulting in a transfer of the change combination code in thesecond register to the first register, thus becoming therein the currentcombination code. The key codes can be placed in set positions forcurrent and next codes, or can be separately identified by means of tagcodes or the like.

The control sequence further causes a new combination code, derived fromthe multi-coded key, to be placed in the second register as the newchange combination code. Thus, the system provides for the use of amulti-coded key for establishing both unlocking and data sourcefunctions. A central station utilizes a code generator to appropriatelyencode the various keys which constitute the sole communication linkbetween the central station and plural access points.

20 Claims, 4 Drawing Figures "1 KEY 84% GR FLAG 72, f 5 READER RESET MDRFLAG co 9'2, MSR FLAG 74 W I4 MDR I20. I21: 1 COMP xeoa 70 76 PositionREGISTER MSR f ianne i is [484 (88 LOCKOUT RESET LINE L 58 -90 7 86LOCKOUT G c o 38 64 a ccoma f a comp N r KEY MD COMB 32 '8 2o DECQDER MSCOMB 40 h, cos/i0 MM- m 5 33 L.: 42 "PM, WC Ms COMP MS coma i we. 34 2LOCK 60MB .44.... 44

H MG COMP] NG COMO 5 46 44 MM m MMD cow ,1

460. NMS comp ELECTRONIC COMBINATION LOCK AND LOCK SYSTEM Prior artelectronic lock systems of the type contemplated herein, as exemplifiedby U.S. Pat. Nos. 3,694,810, 3,673,569, 3,662,342, 3,622,991 and3,599,454, require special wiring to link a central station to each ofthe various access points in the system. This has the distinctdisadvantage of rendering installation very expensive. On the other handstand-alone electronic locks, such as exemplified in U.S. Pat. Nos.3,700,859, 3,688,269, 3,587,051 and others, are not conducive toconvenient changing of the access enabling code, since to do thisrequires adjustment of each lock at the various access points.

One proposed solution to this problem is discussed in copendingapplication Ser. No. 323,098, filed Jan. 19, 1973 and assigned to theassignee of the present invention. As disclosed, in its application in ahotel or motel lock system, such a system is equally applicable to awide variety of security systems where controlled access at a pluralityof remote locations is desired. Thus, a standalone electric combinationlock is provided at each controlled access point. A function generatorincluded in each combination lock generates a current digitally encodedaccess enabling code or combination in conjunction with a digitallyencoded access enabling change code or combination. Electronic logic,upon detection of a match between either one of the internally generatedcombinations and a combination entered by a person seeking access,generates an access enabling signal to, for example, release a lockmechanism. However, when the change combination is matched, the logicadditionally triggers the function generator to generate a newcombination in lieu of the previous current combination and furtherprovides that the previous change combination becomes the current"combination, while the new combination becomes the change combination.Thus, a person equipped with the previous current" combination is deniedaccess, while persons having the now current combination and/or the nowchange combination are afforded access.

The successions of different combination pairs generated by the functiongenerators in the various combination locks follow a predeterminedpseudo-random number sequence which is capable of duplication by acorresponding function generator located at a central station. A memoryat the central station separately stores one or both of the combinationsthen prevailing at each access point. When the appropriate occasionarises, the change combination for the combination look at a selectedaccess point is retrieved from the memory or the change combination isderived by the function generator based on the current combination forthe combination lock at the selected access point as retrieved from thememory and is given to the person or persons authorized for access.

In the illustrated embodiment of the aforementioned copendingapplication, the change combination or, in some instances, the currentcombinationis digitally encoded on a record element, which takes theform of a key, by an encoding mechanism, such as a keymaker. The key isthen taken by the authorized person to the access point where thecombination is entered into the combination lock by a key reader or thelike. It is understood in the aforesaid copending application as well asin the present invention that the key may take a variety of physicalforms and be fashioned from numerous materials. Also, the encodingthereof may utilize a variety of well known techniques. It will also beappreciated that the access enabling combination could be communicatedto the authorized person in a readily intelligible form, such as orallyor imprinted in numeric form, and the authorized person may then enterthe combination via a keyboard or the like to gain access.

In the operation of the device of the aforementioned copendingapplication, a current combination is given to each guest, therebygiving access to the room for which he is registered. When this guestchecks out, the next guest to occupy that room is given the changecombination applicable thereto. The first time the next guest uses hischange combination to access his room, the electronic combination lockautomatically, in effect, cancels the previous current combination todeny room access to the previous guest. The combination possessed bythis next guest becomes the current combination, while the internallygenerated new combination becomes the change combination preparatory forthe arrival of the next subsequent guest.

As an additional feature, the various combination lock functiongenerators each generate current and change combination codes for hotelpersonnel for use as maid or master keys. The electronic combinationlock and central station of the invention utilize the supplementalaccess combinations to afford room access in the same manner as in thecase of the guest combination. The electronic combination lock logic isfurther equipped to respond to special and individually unique lock outcodes given to the guest and which is effective to temporarily inhibitroom access to the maid. In addition, the logic is equipped to respondto reset codes applicable to either guest or maid combinations to permitthe entry of a predetermined access enabling combination to in effectreset the lock to a known point in a pseudo-random number generationsequence. This reset function is necessary in the event the functiongenerator in a particular electronic combination lock unit losessynchronism with the central station or becomes inoperative due toimproved matching of codes.

The requirement of synchronization with a central station is necessaryin the description of the aforementioned copending application sinceeach remote lock generates internally its own successive combinationcodes. While local internal code generation has been found effective toeliminate the difficulties in controlling remote lock units by a centralstation, nevertheless it remains desirable to reduce the synchronizationproblem and simplify the remote units. The provision of functiongenerators within each lock combination unit also presents computationaldifficulties inasmuch as it is necessary to accurately reproduce acomputational feature of a local function generator in order to provideproper central generation and encoding for each successively generatedkey.

It is accordingly the principle object of the present invention toprovide an electronic access system which efficiently overcomes thedrawbacks of the prior art in accordance with the system described inthe aforementioned copending application.

A more specific object of the invention is to provide a system of theabove character wherein each access point or location is non-dependentand functions in stand-alone fashion, without special wiring linking itto a central station.

Still another more specific object of the invention is to provide anon-dependent system of the above character wherein the access enablingcode or lock combination is automatically changed in random,pseudorandom or any other fashion from a central location onappropriate, preselected occasions so as to provide a virtually securesystem.

In accordance with the foregoing objects, it has been discovered thatthe use of a multiple-code key can provide not only the means forenabling access at a remote location, but also the source of combinationcode change control without the necessity of a local function generator.

Accordingly, the present invention provides for a multi-code keycontaining at least a current and next combination code to generate apair of digitally encoded lock combinations. A local access unit isprovided with a key decoder containing storage of current and next codecombinations for one or more functions. In the embodiment disclosed inaccordance with the present invention, a random function generator isnot required at each remote access location. Instead, the multi-codedkey provides the control sequences for enabling the remote access unitlogic to effect its transfer of data from a current to a nextcombination code for response to the appropriate keyed input.

More specifically, each lock unit includes a key decoder with afunctionally assigned pair of registers containing prestored codecombinations. The first register of a pair is designed to store thecurrent combination code. The other register of the pair stores the nextor change combination code. When a key coded with said current andchange combinations is inserted, the current combination carried by thekey is compared with the data stored in each register. If a comparisonis made with the first register, or the second register, an appropriateaccess enable signal is provided. In addition, if a comparison is madewith the second register, logic cir cuitry responds to provide'a controlsequence resulting in a transfer of the change combination code in thesecond register to the first register, thus becoming therein the currentcombination code. The key codes can be placed in set positions forcurrent and next codes, or can be separately identified by means of tagcodes or the like.

The control sequence further causes a new combination code, derived fromthe multi-coded key, to be placed in the second register as the newchange combination code. Thus, the system provides for the use of amulti-coded key for establishing both unlocking and data sourcefunctions.

The foregoing objects and brief description of the present inventionwill become more apparent from the following more detailed descriptionand appended drawings wherein:

FIG. 1 is a logic block diagram of an electronic combination lockconstructed in accordance with the invention for specific application ina hotel lock system;

FIG. 2 is a functional block diagram of the construction of a centralstation adapted for system operation with a plurality of the electroniccombination locks exemplified in FIG. 1;

FIG. 3 is a logic block diagram of one form of a key decoder utilized ineach electronic combination lock of FIG. 1; and

FIG. 4 is a detail of the reset function circuit.

The electronic combination lock, shown in FIG. 1 in a form applicable toa hotel lock system application,

includes a key reader for reading the digitally encoded access enablingcombinations recorded on a key 5 12 inserted therein. The key willcontain two codes,

one a current code, the other a change code. The current code is in afirst position, the change code in a second position. The particularrecording and encoding techniques employed are not material to thepresent invention, but, by way of example, the access enablingcombination may be recorded in the shank of key 12 in the form ofdigitally encoded perforations or holes, such as disclosed in US. Pat.No. 3,688,269. The position of the codes can be distinguishedconveniently, either by virtue of location on the key shank, or by tagbits, or by any other distinguishing technique, and the codestemporarily stored in a position register 14. For illustration, the key12 is shown as including two code positions, 12a and 12b from which itis put out on a data bus 16. The first position 12a code combination inregister 14 is thus supplied over connection 17 to a guest comparator18, over connection 19 to a maid comparator 20, over connection 21 to amaster comparator 22, over connection 23 to a next guest comparator 24,over connection 25 to a next maid comparator 26 and over connection 27to a next master comparator 28. A key decoder 30, included in eachremote electronic combination lock of the invention, responds to datasignals corresponding to the key codes derived from the register 14along the data bus 16 for retaining therein the appropriate codedesignations. The key decoder 30 is also designed to respond to codechanges on the multiple-coded key for altering the retained codedesignations as will be set forth in greater detail below.

The internal structure of the key decoder 30 includes storage to providea current guest combination G COMB in digitally encoded signal form forapplication over connection 31 to the guest comparator 18, a currentmaid combination MD COMB in digitally encoded signal form forapplication over connection 32 to maid comparator 20, a current mastercombination MS COMB for application over connection 33 to next maidcomparator 22, a change or next guest combination NG COMB forapplication over connection 34 to next guest comparator 24, a change ornext maid combination NMD COMB over connection 35 to next maidcomparator 26, and a change or next master combination NMS COMB forapplication over connection 36 to next master comparator 28. If thecombination stored in register 14 and impressed on data bus 16 compareswith any one of the six combinations stored in the key decoder 30, oneof the six comparators 18, 20, 22, 24, 26 or 28 will generate a trueoutput, either G COMP on output lead 38 from guest comparator 18, MDCOMP on output lead 40 from maid comparator 20, MS COMP on output lead42 from master comparator 22, NO COMP on output lead 44 from next guestcomparator 24, NMD COMP on output lead 46 from next maid comparator 26,or NMS COMP on output lead 48 from next master comparator 28. A trueoutput from any one of these comparators is gated through an OR gate 50as an access enabling signal on output lead 52 to a lock mechanism 54.This access enabling signal may serve to initiate actuation of asolenoid, or the like, releasing the lock mechanism to thereby affordroom access to the possessor of key 12.

As long as the access enabling combination entered into register 14 iseither a current guest combination G COMB, a current maid combination MDCOMB, or a current master combination MS COMB, the resulting comparatoroutput, either G COMP, MD COMP or MS COMP is gated through OR gate 50 asan access enabling signal to the lock mechanism. If the person seekingroom access possesses a change combination, i.e., either the next mastercombination NMS COMB, next maid combination NMD COMB or the next guestcombination NG COMB provided by the key decoder 30, the resultingcomparator output, either NMS COMP, NMD COMP or NG COMP, in addition toreleasing lock mechanism 54, is fed back over leads 44a, 46a, 48a to thekey decoder 30. As will be seen more clearly from FIG. 3, the keydecoder 30 operates in response to the receipt of any of these signalsto store a new current combination and a new change combination foreither the master, guest or the maid, as the case may be. In practice,the logic of the key decoder 30 is designed such that the changecombination, NMS COMB, NMD COMB or NG COMB, becomes the currentcombination, MS COMB, G COMB or MD COMB, and the key decoder is, ineffect, reset so as to store a new, next or change combination. The newchange combination is the second combination derived from register 14and is the second position code from the dually encoded key position12b. The logic of the key decoder thus, in effect, adopts this newcombination as the appropriate next or change combination in response tosensing of the original change combination from the key 12.

It is thus seen that the possessor of the key bearing the changecombination is afforded room access while at the same time, triggeringthe electronic combination lock of the invention to change theinternally stored access enabling combinations which must be matched tobe afforded subsequent room access. However, since the changecombination, which precipitated the changing of the lock combination,now becomes the current combination, the possessor of this key isassured subsequent room access since the combination encoded therein isthereafter treated as a current combination and not as a changedcombination. It will be appreciated that possessors of the keys bearingthe previous current combination are denied room access.

In the application of the electronic combination lock of FIG. 1 in ahotel lock system, a registered guest is provided with a key having theguest combination encoded therein for the electronic combination lock tothe room for which he is assigned. Using this key this guest is affordedcontinuing room access. When this guest checks out and a next guest isassigned the same room, a new key encoded with the next guestcombination (changed combination) is issued. The first time this new keyis used in the electronic combination lock, which has stored therein thesame change combination, the access enabling signal is generated to thelock mechanism, the next or change combination becomes the currentcombination, and the new combination contained on the key is now storedas the next or change combination. Maid keys encoded with the maidcombination and the next maid combination are used in the same manner asthe combination encoded guest keys to control room access. Typically, inthe case of the maids, a plurality of electronic combination locks ofthe invention, e.g., those on the same floor, will contain the same maidcombination and next maid combination.

Master keys encoded with the master combination and the next mastercombination are used in the same manner as the combinations encoded onguest keys and maid keys to control room access. Typically, in the caseof master keys, a plurality of electronic combination locks of theinvention, e.g., those for the complete hotel or very large sections ofthe hotel, contain the same master combinations and next mastercombinations.

Still referring to FIG. 1, guests may be provided with a key having aspecial lockout combination encoded therein. This lockout combinationimposed on data bus 16 is compared in a comparator 56 with a lockoutcombination held in a register 58 unique to each electronic combinationlock. When the lockout combinations match, the output of comparator 56sets a flip-flop 60, causing its reset output on lead 62 to go false.This false reset output is supplied as an inhibiting input to the maidcomparator 20 and the next maid comparator 26, with the result that thecomparator outputs MD COMP and NMD COMP otherwise issuing upon the entryinto the electronic lock of the maid and next maid combinations aresuppressed. It is thus seen that the guests can effectively lock out themaid. To remove this lockout function, the guest enters the appropriateaccess enabling combination, either the guest combination G COMB or thenext guest combination NG COMB. The resulting comparator output signal,either G COMP or NG COMP, is gated through OR gate 56 as the accessenabling signal to lock mechanism 54. This access enabling signal isalso gated through an OR gate 64 to force flip-flop 60 to its resetcondition, thereby imposing a true condition on its reset output andthereby removing the inhibiting input from the maid and next maidcomparators 20 and 26.

On occasion, it may become necessary to reset the key decoder 30 of aparticular electronic combination lock to its initial position. As seenin FIG. 1, a reset circuit is provided for generating a guest reset flagdigit GR FLAG which is imposed on output connection 72, a maid resetflag digit MDR FLAG which is imposed on an output connection 74, and amaster reset flag digit MSR FLAG which is imposed on output connection76. The guest reset flag digit is supplied as one input to a comparator78, the maid reset flag digit is supplied as one input to a separatecomparator and the master reset flag digit is supplied as one input to aseparate comparator 82. The other input to each of these comparators isderived from data bus 16. If a guest reset flag digit GR FLAG isgenerated, comparator 78 supplies an output GR COMP on lead 84 to thekey decoder 30, conditioning it to accept the guest reset combinationalso present on data bus 16 and supplied thereto over connection 86. Aswill be seen from FIG. 3, the key decoder 30 derives the next guestcombination NG COMB from the multi-coded key, and thus to reset the keydecoder 30, it is only necessary to enter the key 12 into the key reader10 for placing the new code on the data line 16 for entry into thedecoder 30.

If it is desired to reset the maid combination by using a key 12 encodedwith the appropriate maid reset flag digit, the maid reset combinationis inserted in key reader 10. Recognition of the maid reset flag MDRFLAG on data bus 16 causes comparator 80 to generate a maid reset signalMDR COMP on output lead 88 which is returned to the key decoder 30,conditioning it to accept the maid reset combination appearing on databus 16 and supplied over connection 86. The decoder 30 supplies thismaid reset combination as the maid combination M COMB on outputconnection 32 and the next maid combination NMD COMB which is imposed onoutput connection 34.

If it is desired to reset the master combination by using a key 12encoded with the appropriate master reset flag digit, the master resetcombination is inserted in key reader 10. Recognition of the masterreset flag MSR FLAG on data bus 16 causes comparator 82 to generate amaid reset signal MSR COMP On output lead 90 which is returned to thekey decoder 30, conditioning it to accept the master reset combinationappearing on data bus 16 and supplied over connection 86. The decoder 30supplies this master reset combination as the master combination MS COMBon output connection 33 and the next master combination NMS COMB whichis imposed on output connection 36. The comparator output GR COMP, MDRCOMP and MSR COMP are gated together in an OR gate 92 and supplied overlead 94 to OR gate 64, thereby insuring that flip-flop 60 is reset toremove any pre-existing lockout function. Since the present system isdesigned to be reset only upon power activating of the remote units, theoperation of the reset acts to lock out any further reset by means ofthe signals applied to the reset circuit 70 along lines 84a, 88a and90a.

The administration of a hotel lock system comprising a plurality ofunits each corresponding to the electronic combination lock of FIG. 1 iscarried out at a central station, such as a hotel desk, whose principlesystem components are shown in FIG. 2. As seen therein, these componentsinclude a keyboard 96, a random access memory 98, a key maker 100, andcombination generator 102. Keyboard 96 accesses the memory 98 by roomnumber under which is stored the guest, maid and master combinationsthen being To issue a new guest, maid or master key, memory 98 isaccessed by keyboard 96 under the room number of the room being assignedand the next combination of that room lock which is stored in the keydecoder 30 is retrieved. This combination is routed by a switch 104 tothe key maker. At the same time, a signal is sent to the combinationfunction generator 102 to generate a new random combination with aparity comparison with the combination just previously taken out of thememory 98 and sent to the key maker 100. When this has beenaccomplished, both combinations that are in the key maker are encoded ona key accordingly. If it is desired to issue a duplicate key theappropriate combination is retrieved from memory 98 and routed by switch104 directly to the key maker. Since the combination function generator102 is not operative in this instance, the combination stored in itsassigned memory location is unaltered. Similarly, should a guest desirea maid lockout key, memory 98 is accessed by keyboard 96 to retrieve thelockout combination for the electronic combination lock to the guestroom, and this combination is routed by switch 104 directly to the keymaker 100.

To issue a guest or maid reset combination for a particular room, memory98 is accessed and the reset flag digit and reset combinations arerouted by switch 104 directly to the key maker. In this instance, asecond switch 106 is closed such that the reset combination retrievedfrom the memory is stored as the guest combination G COMB, maidcombination MD COMB, or

master combination MS COMB, as the case may be, in place of thecombination previously stored there. This reset combination then becomesthe current combination affording room access. With the arrival of thenext guest, the reset combination is retrieved from memory and suppliedto the function generator through routing switch 104 with switch 106open. The function generator 102 then generates the next guestcombination which is returned to memory 98 and also used by the keymaker to encode this next guests key.

The function generator 102 (FIG. 2) at the desk may comprise an adderand a fixed increment register in order to derive the next combinationsfor the various electronic combination locks based on their currentcombinations as retrieved from memory 108.

It will be appreciated that the function generator 102 may in practicebe considerably more complex and so- .phisticated to enhance thesecurity of the lock system.

For example, the function generator 108 may be a trigonometric functiongenerator or a logarithmic function generator. Alternatively, a randomnumber generator may be employed which uses the prior next guest, maidor master combinations as seed numbers for generating the nextcombinations in accordance with a pseudorandom number algorithm, or withany random sequence or selection scheme. Since synchronism is notrequired between the central station and each lock unit, the successivecombinations can be generated in any desired manner.

Other alternative forms of central stations may be employed. The centralstation memory can be limited merely to some form of simple storage foronly one prior code combination, that found in the second position onthe key. Since the system allows the key itself to control the locksettings, it is only necessary that the central station issue a new keyhaving the prior key second combination in the new key first combinationposition, and a new second combination recorded in the new key secondcombination position. It is thus within the scope of the invention toemploy a storage device responsive to the codes on a prior key torandomly generate a new code combination, re-code the original secondcode on the new key units first code position, and place the newlygenerated code on the new key in its second position. In this lattercase, a memory need be only a temporary storage register and accessingstored locations need not be necessary. However, it is preferable tohave some means of retaining the next combination code, either by makinga duplicate key to be kept at the central station, or electronically, asin a central memory such as is shown in FIG. 2.

Referring now to FIG. 3, the key decoder 30 is illustrated in greaterdetail.

The decoder 30 included three sections establishing the code combinationsequences for each respective lock function input. Thus, section 110 isapplicable to guest combination codes, section 112 is applicable to maidcombination codes and section 114 is applicable to master combinationcodes. It will be appreciated that greater or lesser numbers of sectionsmay be employed in accordance with the desired functions to be utilizedat the remote unit in response to the data inputs applied thereto.

Each section includes a first register for storing current combinations,a second register for storing next or change combinations, and logiccircuitry for affecting the manipulation of the data upon applicationthereto by. the coded input device. Thus, with applicability to thehotel locking system described hereinabove, sec tion 110 includes aguest register 120 for storing the current guest combination, a register122 for storing the next or change guest combination, a multiplexingdevice 124 for controlling the data manipulation and a first OR gate 126and a second OR gate 128 for channeling NG compare and G reset signalsto the registers 120 and 122.

Section 112 includes a maid register 130 for storing the current maidcombination, a register 132 for storing the next or change maidcombination, a multiplexing device 134 for controlling the datamanipulation, and a first OR gate 136 and a second OR gate 138 forchanneling NMD compare and MD reset signals to the registers 130 and132. Section 114 includes a master register 140 for storing the currentmaster combination, a register 142 for storing next or change mastercombination, a multiplexing device 144 for controlling the datamanipulation, and a first OR gate 146 and a second OR gate 148 forchanneling NMS compare and MS reset signals to the registers 140 and142.

The initial condition for a remote unit lock is established by resettingeach of the registers to an initial or zero information state. Resettingcan be accomplished at the lock during power installation, particularlyin a remote locking unit environment wherein batteries may be employedto power the units. Upon establishment of power, the circuitry of thelock sets each of the bits in all of the registers to zero. At thispoint, each of the registers is set to receive information placedtherein by means of a data input mechanism, in this case the key 12,through the key reader and the register 14. The multicoded key containstwo combinations for filling the two appropriate registers. For example,a guest key contains a guest and next guest combination. The code datafrom the guest key is applied along data bus 16 from the register 14 andapplied in section 110 to the guest register 120 through the multiplexer124 and to the next guest register 122 directly along the line 122a. Themaid and master registers are similarly filled by the insertion of anappropriate key. Distinction between the various registers may beestablished by means of a code bit for gating the proper informationinto the appropriate registers in accordance with conventional logictechniques. .Once stored, the use of subsequent code combinationsimpressed upon the data bus 16 as a result of repeated use of the keydevice 12 into the key reader 10 will set forth the chain of sequentialevents noted in connection with FIG. 1 for opening the lock 64. Thus, acomparison between the key entry data and the data stored in any of thesix registers, 120, 122, 130, 132, 140 or 142 will provide anappropriate true output on the output of the appropriate respectiveregister in accordance with the data input applied. lf, for example, aguest combination code is applied along the data bus 16, a true outputwill be generated by the guest comparator 18 in accordance with thesimilarity of inputs along the input line 17 and the line 31 from theguest register 120. The true output from the guest comparator 18 alongthe line 38 to the OR gate 50 will apply an appropriate access enablingunlocking pulse along the line 52 to the lock 54. This access enablingsignal will thus activate the lock and release the lock mechanism. Thus,as long as the access enabling combination entered into the register 14and applied along data bus 16 is either a current guest combination, acurrent maid combination or a current master combination, the resultingregister output will be gated through the OR gate 50 as an accessenabling signal for the lock mechanism.

If a person seeking room access possesses a key with a changecombination, i.e. the combination either residing in any of the secondregisters in each of the sections 110, 112 and 114, the resultingregister output in addition to releasing the lock mechanism is fed backto the appropriate multiplexer unit. Thus, referring to sectionspecifically, receipt of the next guest compare signal along the databus 16 will result in a similarity of outputs along lines 23 and 34 tothe next guest comparator 24 resulting in a true output along the line44. As noted, the true output is applied through the OR gate 50 alongthe line 52 for unlocking the lock mechanism 54. In addition, thissignal is fed back along the line 44a to the key decoder 30 where it isapplied to the OR gates 126 and 128. Application of pulses through theOR gates 126 and 128 result in the code combination of the next guestregister 122 being shifted along the output line 122b to the multiplexer124 for entry into the guest register as the new current combination. Asa result, the new next guest combination derived from the multi-codedkey as applied along the data bus 16 will be entered directly intoregister 122 along the appropriate input connections 122a. The originalcur rent guest combination stored in register 120 is effectivelydestroyed by the replacement thereof by the new guest or next guestcombination received from the next guest register 122 along the line122b, through the multiplexer 124 and into the guest register 120. It isthus seen that the possessor of the key bearing the change combinationis afforded room access while at the same time triggering the electroniclock of the invention to change the internally stored access enablingcombinations which must be matched to be afforded subsequent roomaccess. However, since the change combination which precipitated thechanging of the lock combination now becomes the current combination,the possessor of this key is assured subsequent room access since thecombination encoded therein is thereafter treated as the currentcombination and not as a change combination. It will be appreciated thatthe possessors of the keys bearing the previous current combination arenow denied room access. The same operative principle is applied tosections 112 and 114.

When the .situation arises to reset the guest, maid or mastercombination, the appropriate reset flag digit and reset combination,code are entered into the electomic combination lock of FIG. 1 via thekey reader 10 as previously described. For example, if the guest combination is to be reset, and the GR FLAG 72 is set, the entry of theguest reset flag digit causes the comparator 78 to generate the outputGR COMP on lead 84 to the OR gates 126 and 128 and the multiplexer 124.The GR COMP signal conditions multiplexer 124 to connect the data bus 16via the connection 86 to the input of the guest combination register120. The GR COMP signal also supplied to the OR gates 126 and 128conditions both registers 120 and 122 to accept the new data beingapplied along the data bus 16. Thus both the guest register 100 and thenext guest register 122 will be loaded with their respective data fromthe key 12 present on bus 16. Reset of the maidand master section 112and 114 is accomplished in precisely the same manner.

Referring now to FIG. 4, there is illustrated a circuit showing thatgeneration of reset flags occurs only upon initializing the lockelectronics and allowing the lock to accept a reset key for executingthe functions for guest, maid or master reset. As shown in FIG. 4, apower on reset circuit includes a potential source 200 connected acrossa switch 202. A resistance 204 and a capacitor 206 are coupled acrossthe switch 202. For the guest reset flag GR FLAG, a logical AND gate 208is provided with a first input coupled to the junction of the resistance204 and the capacitor 206 and a second input coupled to the complimentedoutput of the flipflop 210. For the maid reset flag MDR FLAG, a logicalAND gate 212 is provided with a first input coupled to the junction ofthe resistance 204 and the capacitance 206 and a second input coupled tothe complimented output of the flip-flop 214. For the master reset flagMSR FLAG, a logical AND gate 216 is provided with the first inputcoupled to the junction of the resistance 204 and the capacitor 206 anda second input coupled to the complimented output of the flip-flop 218.The flip-flop 210 received the guest reset compare input along line 84a,the flip-flop 214 receives a maid reset compare input along the line88a, and the flip-flop 218 receives its master reset compare input alongthe line 90a. A power on reset signal indicating reapplication of thepower from the source 200 is applied along the line 220 commonly to thereset inputs of each of the flipflops 210, 214 and 218.

In operation, the power on reset condition is provided by virtue of theswitch 202 which is in a normally open position when the circuit is inoperation. If the voltage source 200 is removed for replacement, theswitch 202 is mechanically closed for discharging the capacitor 206.Upon reinstallation of the power source 200, the switch 202 70 potentialcharge any is designed to be sufficient to allow all circuitry to becomeenergized, and the flip-flops 210, 214 and 218 to assume their normalcondition with a complimented output Q at a logical one. When thecapacitor 205 is fully charged, the output of the respective AND gates208, 212 and 216 each indicate a logical one, thereby signifying enabledreset flags. The significance of enabled reset flags is that a new powersource has been positioned and the circuitry thus prepared for receiptof new combinational codes. As each new key and its combination codesare reinserted, an appropriate pulse appears along the appropriatecompareline 84a, 88a and 90a. The presence of each of these respectivesignals will be to set each of the respective flip-flops, 210, 214 and218 receivin the inputs thereon, causing the complimented output o to goto zero and thereby disabling each of the respective AND gates 208, 212and 216 in accordance with the input condition applied thereto. Thereset flag thus is disabled and remains disabled until power is againremoved and reapplied, as described above. For security, the system isthus designed to be reset only by removal and replacement of the powerunit, thereby preventing users of a resetting key from gaining access byresetting the lock and inserting an unauthorized combination code.

Since, in this system, it is the key that carries the combinations tothe locks for entry into the storage of the key decoder 30 of eachelectronic lock, additional security must be added in order to preventthe bearer of a present key from gaining knowledge of the informationcontained on that key for the next combination. To enchance the securityof the next combination, which may be typically perforated, punched orencoded in some way on the key, the arrangement of the next combinationon the key is mixed with the present combination. In addition, the bitpattern arrangement of the next combination found on the present keycombination is rearranged completely when that next combination appearsas the present combination on a subsequently issued key. Thistransferring or scrambling of the present and next combination on a keymay be handled conveniently within the lock unit by any conventionalform of scrambler or descrambler. For example, if the present and nextcombination codes are each represented by a four bit binary code, thepresent code may be formed by bits number one, three, five and six,while the next combination by bits number two, four, seven and eight.The key reader and key maker merely provide the appropriate datatransducing for each code to the assigned bit positions, thus making thekey itself unintelligible to an observer or key reader not equipped withthe appropriate bit designations.

From the foregoing description, it is seen that the present inventionincludes all the advantages of an electronic combination lock systemincluding a plurality of electronic combination locks which areconducive to being administered from a central location withoutrequiring electrical connections therebetween. The only link between thecentral station and the various electronic combination locks of theinvention are the combination encoded keys possessed by those personsauthorized for access. Consequently, no special wiring is required toimplement the lock system of the invention. Since the combinations ofthe various electronic combination locks of the invention can be changedsimply by using a new key encoded with the appropriate changecombination there is no necessity for security personnel to visit eachaccess point to adjust the lock thereat. Moreover, upon use of thechange combination, possessors of the previous access enablingcombinations who are no longer authorized access are automaticallydenied future access.

It will thus be seen that the objects set forth above, among those madeapparent from the preceding description are efficiently attained and,since certain changes may be made in the above construction withoutdeparting from the scope of the invention, it is intended that allmatter contained in the above description or shown in the accompanyingdrawings should be interpretated as illustrative and not in a limitingsense.

Having described the invention, what is claimed as new and desiredtosecure by Letters Patent is:

1. A combination lock comprising, in combination:

A. entry means for accepting first and second lock combination entries;

B. first logic means for establishing first and second stored lockcombinations;

C. comparing means responsive to a match between a first lockcombination entry and either one of said first and second stored lockcombinations for developing an access enabling signal; and

D. .second logic means responsive to a match be tween a first lockcombination entry and said second stored combination for controllingsaid first logic' means to replace said first stored combination withsaid second stored combination, and said secnd stored combination withthe second lock combination entry associated witth said first lockcombination entry.

2. An electronic combination lock comprising, in combination:

A. a lock mechanism;

B. means for generating a digital readout of an encoded lock combinationborne by a key;

C. a key decoder for storing first and second digitally encoded lockcombinations;

D. a first comparator for comparing said first lock combination withsaid key readout and, upon comparison, generating a first compare signaleffective to initiate actuation of said lock mechanism;

E. a second comparator for comparing said second lock combination withsaid key readout, and, upon comparison, generating a second comparesignal also effective to intiate actuation of said lock mechanism; and

F. logic means responsive to said second compare signal for cancellingsaid first stored lock combination and to store a third digitallyencoded lock combination derived from said key.

3. An electronic combination lock system comprising in combination;

A. an electronic combination lock located at each of a plurality ofaccess points, each of said locks including 1. a lock mechanism,

2. means for reading and generating a plurality of digital combinationkey-readout codes from an encoded lock combination borne by a key,

3. means for storing first and second digitally encoded lock combinationcodes,

4. a first comparator responsive to a comparison between said firststored lock combination code and a key readout code for generating afirst compare signal effective to initiate actuation of said lockmechanism,

5. a second comparator responsive to a comparison between said secondstored lock combination code and a key readout code for generating asecond compare signal effective to initiate actuation of said lockmechanism, and

6. logic means responsive to said second compare signal for respectivelyreplacing said first stored lock combination code with said secondstored lock combination code and said second stored lock combinationcode with a key readout code, and

B. a central station including 1. first means for providing at leastsaid second lock combination code for a selected one of said electroniccombination locks,

2. second means for generating a next successive lock combination code,and

3. recording means for entering said second lock combination code andsaid next successive lock combination code on said key.

4. The combination of claim 3 wherein said first means includes a memoryfor storing digitally encoded lock combination codes.

5. The combination of claim 4 wherein said first means includes meansfor accessing said memory to retrive the second stored lock combinationcode for a se lected one of said electronic combination locks.

6. The combination of claim 3 wherein said second means includes arandom number generator.

7. The combination of claim 5 wherein said second means includes arandom number generator for deriving the said next successive lockcombination code in respect to said retrieved lock combination code in arandom sequence for said selected one of said electronic combinationlocks, and means for entering said next successive lock combination codein said memory.

8. A lock system comprising a multiple coded key having at least firstand second combination code positions, a lock including storage meanshaving a first storage location for storing a first code and a secondstorage location for storing a second code, the lock including meansresponsive to a match between a key combination code in said firstcombination code position and said first stored code for providing anaccess enabling signal, and the lock including means responsive to saidcontrol signal for transferring said second stored code from said secondstorage location to said first storage location and for placing the keycombination code in said second combination code position into saidsecond storage location.

9. The lock system of claim 8 wherein said storage means includes firstand second registers respectively having said first and second storagelocations, and wherein said lock system includes means for resettingsaid first and second registers to a predetermined condition.

10. The lock system of claim 8 wherein said first and second storagelocations include a plurality of sections, each of said sections havingfirst and second storage locations, and said lock includes meansresponsive to a predetermined combination code for rendering selectiveones of said sections inoperative.

11. The lock system of claim 8 wherein said lock includes a resetcircuit, said reset circuit including means for providing a resetsignal, and said lock includes compare means responsive to said resetsignal and a further combination code on said key for resetting saidfirst and second codes to codes derived from codes at said first andsecond combination positions of said key, and said reset circuit beingfurther responsive to said compare means for disabling said resetsignal.

12. An electronic combination lock system comprising in combination amultiple coded key having at least first and second combination codepositions, a lock including storage means having a first storagelocation for storing a first code and a second storage location forstoring a second code, the lock including means responsive to a matchbetween the combination code in said first combination code position andsaid first stored code for providing an access enabling signal, the lockincluding means responsive to a match between the combination code insaid first combination code position and said second stored code forproviding an access enable signal and a control signal, the lockincluding means responsive to said control signal for respectivelytransferring said second stored code from said second storage locationto said frist storage location and placing the combination code in saidsecond combination code position into said second storage location, acentral station including first means for providing at least said secondcombination code for a selected one of said electronic combinationlocks, and said central station including second means for generating anext successive combination code and recording means for entering saidsecond combination code and said next successive combination code onsaid key.

13. The combination of claim 12 wherein said storage means includes afirst register having said first storage location and a second registerhaving said second storage location, and wherein said lock systemincludes reset means for resetting said first and second storageregisters to a predetermined condition.

14. The combination of claim 12 wherein said first and second storagelocations include a plurality of sections, each of said sections havingfirst and second storage locations, and said lock including meansresponsive to a predetermined combination code for rendering selectiveones of said sections inoperative.

15. The combination of claim 12 wherein the lock includes a resetcircuit, said reset circuit including means for providing a resetsignal, compare means responsive to said reset signal and a further codecombination on said key for resetting the codes in said first and secondstorage locations in accordance with codes derived from the codes atsaid first and second combination code positions of said key, and saidreset circuit being further responsive to said compare means fordisabling said reset signal.

16. The combination of claim 12 wherein said first means includes amemory for storing digitally encoded lock combination codes.

17. The combination of claim 16 wherein said first means includes meansfor accessing said memory to retrieve the stored lock combination codefor a selected one of said electronic combination locks.

18. The combination of claim 12 wherein said second means includes arandom number generator. sequence and means 19. The combination of claim17 wherein said second means includes a random number generator forderiving the next successive lock combination code in respect to saidretrieved lock combination code in a random sequence for said selectedone of said electronic combination locks, and means for entering saidncxt successive lock combination code in said memory.

20. A combination lock programmable by means of a code bearing key, saidlock comprising, in combination:

A. means for accepting first and second lock combination entry codesborne by the key; B. lock programming means programmed to store firstand second lock combination access codes; C. comparing means responsiveto a match between a first lock combination entry code and either one ofsaid first and second lock combination access codes for developing anaccess enabling signal, and D. logic means responsive to a match betweena first lock combination entry code and said second lock combinationaccess code for controlling said lock programming means to respectivelyreplace the first and second stored access codes with the second storedaccess code and second entry code, whereby the second stored access codebecomes a new first stored access code and the second entry code becomesa new second stored access code.

1. A combination lock comprising, in combination: A. entry means foraccepting first and second lock combination entries; B. first logicmeans for establishing first and second stored lock combinations; C.comparing means responsive to a match between a first lock combinationentry and either one of said first and second stored lock combinationsfor developiNg an access enabling signal; and D. second logic meansresponsive to a match between a first lock combination entry and saidsecond stored combination for controlling said first logic means toreplace said first stored combination with said second storedcombination, and said second stored combination with the second lockcombination entry associated witth said first lock combination entry. 2.means for reading and generating a plurality of digital combinationkey-readout codes from an encoded lock combination borne by a key,
 2. Anelectronic combination lock comprising, in combination: A. a lockmechanism; B. means for generating a digital readout of an encoded lockcombination borne by a key; C. a key decoder for storing first andsecond digitally encoded lock combinations; D. a first comparator forcomparing said first lock combination with said key readout and, uponcomparison, generating a first compare signal effective to initiateactuation of said lock mechanism; E. a second comparator for comparingsaid second lock combination with said key readout, and, uponcomparison, generating a second compare signal also effective to intiateactuation of said lock mechanism; and F. logic means responsive to saidsecond compare signal for cancelling said first stored lock combinationand to store a third digitally encoded lock combination derived fromsaid key.
 2. second means for generating a next successive lockcombination code, and
 3. An electronic combination lock systemcomprising in combination: A. an electronic combination lock located ateach of a plurality of access points, each of said locks including 3.recording means for entering said second lock combination code and saidnext successive lock combination code on said key.
 3. means for storingfirst and second digitally encoded lock combination codes,
 4. a firstcomparator responsive to a comparison between said first stored lockcombination code and a key readout code for generating a first comparesignal effective to initiate actuation of said lock mechanism,
 4. Thecombination of claim 3 wherein said first means includes a memory forstoring digitally encoded lock combination codes.
 5. The combination ofclaim 4 wherein said first means includes means for accessing saidmemory to retrive the second stored lock combination code for a selectedone of said electronic combination locks.
 5. a second comparatorresponsive to a comparison between said second stored lock combinationcode and a key readout code for generating a second compare signaleffective to initiate actuation of said lock mechanism, and
 6. Thecombination of claim 3 wherein said second means includes a randomnumber generator.
 6. logic means responsive to said second comparesignal for respectively replacing said first stored lock combinationcode with said second stored lock combination code and said secondstored lock combination code with a key readout code, and B. a centralstation including
 7. The combination of claim 5 wherein said secondmeans includes a random number generator for deriving the said nextsuccessive lock combination code in respect to said retrieved lockcombination code in a random sequence for said selected one of saidelectronic combination locks, and means for entering said nextsuccessive lock combination code in said memory.
 8. A lock systemcomprising a multiple coded key having at least first and secondcombination code positions, a lock including storage means having afirst storage location for storing a first code and a second storagelocation for storing a second code, the lock including means responsiveto a match between a key combination code in said first combination codeposition and said first stored code for providing an access enablingsignal, and the lock including means responsive to said control signalfor transferring said second stored code from said second storagelocation to said first storage location and for placing the keycombination code in said second combination code position into saidsecond storage location.
 9. The lock system of claim 8 wherein saidstorage means includes first and second registers respectively havingsaid first and second storage locations, and wherein said lock systemincludes means for resetting said first and second registers to apredetermined condition.
 10. The lock system of claim 8 wherein saidfirst and second storage locations include a plurality of sections, eachof said sections having first and second storage locations, and saidlock includes means responsive to a predetermined combination code forrendering selective ones of said sections inoperative.
 11. The locksystem of claim 8 wherein said lock includes a reset circuit, said resetcircuit including means for providing a reset signal, and said lockincludes compare means responsive to said reset signal and a furthercombination code on said key for resetting said first and second codesto codes derived from codes at said first and second combinationpositions of said key, and said reset circuit being further responsiveto said compare means for disabling said reset signal.
 12. An electroniccombination lock system comprising in combination a multiple coded keyhaving at least first and second combination code positions, a lockincluding storage means having a first storage location for storing afirst code and a second storage location for storing a second code, thelock including means responsive to a match between the combination codein said first combination code position and said first stored code forproviding an access enabling signal, the lock including means responsiveto a match between the combination code in said first combination codeposition and said second stored code for providing an access enablesignal and a control signal, the lock including means responsive to saidcontrol signal for respectively transferring said second stored codefrom said second storage location to said frist storage location andplacing the combination code in said second combination code positioninto said second storage location, a central station including firstmeans for providing at least said second combination code for a selectedone of said electronic combination locks, and said central stationincluding second means for generating a next successive combination codeand recording means for entering said second combination code and saidnext successive combination code on said key.
 13. The combination ofclaim 12 wherein said storage means includes a first register havingsaid first storage location and a second register having said secondstorage location, and wherein said lock system includes reset means forresetting said first and second storage registers to a predeterminedcondition.
 14. The combination of claim 12 wherein said first and secondstorage locations include a plurality of sections, each of said sectionshaving first and second storage locations, and said lock including meansresponsive to a predetermined combination code for rendering selectiveones of said sections inoperative.
 15. The combination of claim 12wherein the lock includes a reset circuit, said reset circuit includingmeans for providing a reset signal, compare means responsive to saidreset signal and a further code combination on said key for resettingthe codes in said first and second storage locations in accordance withcodes derived from the codes at said first and second combination codepositions of said key, and said reset circuit being further responsiveto said compare means for disabling said reset signal.
 16. Thecombination of claim 12 wherein said first means includes a memory forstoring digitally encoded lock combination codes.
 17. The combination ofclaim 16 wherein said first means includes means for accessing saidmemory to retrieve the stored lock combination code for a selected oneof said electronic combination locks.
 18. The combination of claim 12wherein said second means includes a random number generator. sequenceand means
 19. The combination of claim 17 wherein said second meansincludes a random number generator for deriving the next successive lockcombination code in respect to said retrieved lock combination code in arandom sequence for said selected one of said electronic combinationlocks, and means for entering said next successive lock combination codein said memory.
 20. A combination lock programmable by means of a codebearing key, said lock comprising, in combination: A. means foraccepting first and second lock combination entry codes borne by thekey; B. lock programming means programmed to store first and second lockcombination access codes; C. comparing means responsive to a matchbetween a first lock combination entry code and either one of said firstand second lock combination access codes for developing an accessenabling signal, and D. logic means responsive to a match between afirst lock combination entry code and said second lock combinationaccess code for controlling said lock programming means to respectivelyreplace the first and second stored access codes with the second storedaccess code and second entry code, whereby the second stored access codebecomes a new first stored access code and the second entry code becomesa new second stored access code.